Measuring instrument having capsules



Sept. 2, 1941. c.- H. H. RODANET MEASURING INSTRUMENT HAVING CAPSULES 2Sheets-Sheet 1 Filed May 14;} 1940 Fie.1.

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MEASURING INSTRUMENT HAVING CAPSULES Filed May 14, .1940 2 Sheets-Sheet2 CHARLES was mi Row HTTORIISY-S Patented Sept. 2, 1941 Charles HilaireHenri Rodanet, Neuilly-sur- Seine, France, assignor to Socit Anonymer Jaeger-Aviation, Levallols-Perret, Seine, France Application May 14,1940, Serial No. 335,084

In France June 2, 1939 2 Claims.

The present invention has for object improvements in measuringinstruments provided with capsules, operating in particular, under theaction of a fluid under pressure or under partial vacuum,

in order that the apparatus should have several degrees of sensitivenessaccording to the values of the pressure or of the partial vacuum of thefluid.

The improvements according to the invention are mainly characterized bythe fact that the measuring instrument comprises at least two capsulessimultaneously subjected to the action of the fluid and so arranged thattheir distortions are added to each other, one of them being howeversubjected to the action of abutments, which are preferably adjustable,and allow:of determining at will the limits (beginning and end) of itsdistortion relatively to the distortion of the other capsule.

For instance:

' (a) an abutment can be provided which limits the distortion of thefirst capsule to a certain value. Until this value is obtained, thedistortions of both capsules are added to each other and the instrumenthas great sensitiveness; but beyond this value the second diaphragmalone distorts and the sensitiveness diminishes.

b)' an abutment can be provided by means of which the first capsule issubjected to an initial distortion corresponding to the predeterminedvalue. Until this value is obtained the second diaphragm alone distorts,andthe sensitiveness is reduced; but thereafter, the distortions of bothdiaphragms are added and the sensitiveness is increased.

(c) both abutment systems can finally be provided, which allows ofdetermining at will the lower and upper limits of the zone of highsensitiveness.

Preferably, the capsules are simultaneously subjected to the action ofthe fluid by causing them to directly communicate together.

The abutments can be fixed but it is advantageous to make themadjustable.

The invention includes all measuring apparatus comprising not only two,but more than two capsules, the various capsules acting simultaneouslybetween certain definite values, the distortions of said capsules beingoutside said limited values successively and in stages, orsimultaneously, so as to obtain a series of difi'erent sensitivenesses.

The invention also includes thenew industrial products constituted bymeasuring apparatus ters or the like having a plurality of capsules asabove defined.

Other particular points, also included in the scope of the presentinvention will appear in the following text given with reference totheaccompanying drawings, by way of example only, in which:

Fig. l is a general elevation, in axial section, v

of a double capsule system for an anemometer in a first embodimentcooperating with a Pitot' tube. I

Fig. 2 is a front view of the dial of the speed indicator of theanemometer.-

Fig. 3 is an elevation relating to a second em- I branched, forinstance, on an air-intake.

The face l of capsule l and the face 2 of capsule 2 are renderedcentrally rigid with a common intermediate member 4 perforated at 5 forputting both capsules in communication together and which is providedwith an axial tail piece 6. This tail piece 6 engages-in the tubularsuch as anemometers, pressure-gauges, altimemember 3 and comprises anadjusting nut I which limits, with a shoulder 3 of member 3, a stroke dcorresponding to the maximum distortion whichcan be reached by the walll relatively to the wall I.

It will be noted that the central part of the wall 2 of capsule 2comprises a fork 8 for connection to indicating means for instance.

The operation of the device previously described is as follows:

In position of rest, the various members occupy the position illustratedin Fig. 1. As soon as the fluid under pressure acts in the tubularmember 3, said pressure immediately exists-in capsule l andrin capsule 2which are in communication through the passage 5.

Both capsules I and 2 simultaneously distort in the direction of thearrow 9, the sensitiveness.

The communication between the tubular member 3 and the first capsule Iis ensured either solely through the axial passage III in which passesthe tail piece 6 with a certain amount of play, or both through saidpassage and perforations'provided around said passage so that theapplication of nut I on the shoulder 3 does not cut off thecommunication between said member 3 and thefirst capule I.

In the example illustrated, the fork 8 controls,

.through the medium of a suitable gearing-up device, the rotation of anindex II movable opposite graduations I2 extending over 360 degrees.These graduations bear indications in kilometers per hour.

On board an aeroplane for instance, the pilot must be informed veryaccurately of the speed of his aeroplane relatively to the relative windbetweenO and 200 kilometers per hour in particular, in modernaeroplanes. In fact, during any range of speeds he must effect delicateoperations and in particular, flying off or landing. In theseconditions, the double sensitiveness of both capsules I and 2 actsbetween (land 200 kilometers per hour, these graduations occupying 180degrees. The other part, that is to say 180 degrees, is graduated from200 to 600 kilometers per hour, the index I I being only subjected tothe single sensitiveness of the capsule 2.

In the example of Figs. 3 and 4, therod 6 receives a second nut I3 whichcooperates with an abutment I4 in such a manner that the diaphragm I ofcapsule I is initially subjected to a certain distortion correspondingto a given value of the pressure. is for instance that obtained when theaeroplane moves at 200 kilometers an hour) the capsule 2 acts alone, andthe sensitiveness between and 200 is single. From this value, thesensitiveness is double, until the nut 1 comes in contact with theabutment 3 which corresponds -for instance to 480 kilometers an hour.The op- Up to this value (which of Fig. 3 is in contact with theabutment 3, be-

cause it exerts on capsule I an initial flattening stress; and, on thecontrary, the nut I3 is at a suitable distance from the abutment I4 forstopping, after a certain stroke, the flattening of said capsule I. Theoperation is obviously identical to the preceding one.

It will be noted that with capsules of different characteristics,anyvariations of sensitiveness can be obtained and not only variations in asingle ratio.

What I claim as my invention and desire to se cureby Letters Patent is:v 1. In an apparatus for measuring the pressure of fluids, of the typecomprising distortable fluidtight capsules, a first capsule having awall centrally secured to a fixed conduit admitting the fluid thepressure of which is to be measured, a second capsule juxtaposed on thefirst one, a connection interposed between the central parts of theadjacent walls of both capsules for rigidly connecting said walls, saidconnection being perforated for causing the capsules to communicatetogether, a rod rigidly secured on said connection and adapted to extendwithin the conduit admitting the fluid in the first capsule, an abutmenton said rod for limiting the distortions of the first capsule, and meanson the outer wall of the last capsule of the series for allowing toconnect the same to the usual indicating means.

2. In an apparatus for measuring the pressure of fluids, of the typecomprising distortable fluidtight capsules, a first capsule having awall centrally secured to a fixed conduit admitting the fluid thepressure of which is to be measured, a second capsule juxtaposed on thefirst one, a connection interposed between the central parts of theadjacent walls of both capsules for rigidly connecting said walls, saidconnection being perforated for causing the capsules to communicatetogether, a rod rigidly secured on said connection and adapted to extendwithin the conduit admitting the fluid in the first capsule, a firstadjustable abutment on said rod cooperating with an abutment on saidconduit for allowing to impart an initial tension to the outer wall ofthe first capsule, a second abutment on said rod for limiting thedistortions of the first capsule and means on the outer Wall of the lastcapsule of the series for allowing to connect the same to the usualindicating means.

CHARLES HILAIRE HENRI RODANET.

